Ladder-based winch-powered plank scaffold

ABSTRACT

A plank scaffold system and, more particularly, to a ladder-based vertically-adjustable plank scaffold system. The system may have a pair of ladders, a wall standoff mounted at the top of each of the ladders, a crane support mounted at the top of each of the ladders, a vertical guide bar and roller system to keep it from swinging on the cables, and a horizontal platform suspended on cables below the crane supports, the platform having a pair of cable winches mounted thereon for varying the elevation of the platform. Instead of ladders, tower scaffolds or stage towers may be used on each side to support the vertically-adjustable plank.

RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. application Ser. No. 16/987,940, filed Aug. 7, 2020, now U.S. Pat. No. 11,280,097, issued Mar. 22, 2022, which claims priority to provisional application No. 62/883,985 filed Aug. 7, 2019, under the same title, which is incorporated herein by reference in its entirety.

NOTICE OF COPYRIGHTS AND TRADE DRESS

A portion of the disclosure of this patent document contains material which is subject to copyright protection. This patent document may show and/or describe matter which is or may become trade dress of the owner. The copyright and trade dress owner have no objection to the facsimile reproduction by anyone of the patent disclosure as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright and trade dress rights whatsoever.

BACKGROUND Field

This disclosure relates to a plank scaffold system and, more particularly, to a ladder-based vertically-adjustable plank scaffold system.

Description of the Related Art

Swing Stage platform scaffolds are ubiquitous in cities, where they are suspended from tall building roofs and two cable winches on board operating in tandem gradually lower the platform down the building exterior for window washing and other tasks. For jobs on the outside of smaller structures, such as painting and window washing, a portable scissor lift is often used. However, such a system is relatively expensive to lease and thus not economic for small jobs. In other systems, parallel tall ladders with scaffolding in between have been proposed. For instance, a mobile ladder-scaffolding system seen in U.S. Pat. No. 4,232,759 involves two rigidly fixed ladders that are laterally movable along tracks and support a platform at various elevations. This system is relatively complicated and requires guiding structure on the roof of the building on which the work is being done.

Despite numerous solutions proposed for smaller platform scaffolds, there remains a need for an easy-to-use and economical system that may be set up by one or two workmen.

SUMMARY OF THE INVENTION

According to exemplary embodiments, a ladder-based winch-powered plank scaffold is provided. The ladder-based vertically-adjustable plank scaffold system may have a pair of ladders, a wall standoff mounted at the top of each of the ladders, a crane support mounted at the top of each of the ladders, and a horizontal platform suspended on cables below the crane supports, a roller guide bar to keep the platform from swinging, the platform having a pair of cable winches mounted thereon for varying the elevation of the platform. Instead of ladders, tower scaffolds or stage towers may be used on each side to support the vertically-adjustable plank.

One version modifies the standoff legs to be telescopic so they are shorter when not in use so as not to throw off your balance when lifting or carrying ladders vertically during setting up the scaffold.

Another useful variation is to extend the crane arm all the way to the wall, bend it downward and connect it to the roller guide bar. This eliminates the upper stabilizer bar and also functions to bear some of the weight so the standoffs do not bear it all.

Other features and characteristics of the present invention, as well as the methods of operation, functions of related elements of structure and the combination of parts, and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures.

DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a first embodiment of a ladder-based plank scaffold system embodying aspects of the present application, and FIG. 1B is a side elevational view thereof.

FIG. 1C is a perspective view of an alternative embodiment of a ladder-based plank scaffold system similar to the first but without dedicated platform stabilizer bars;

FIG. 1D is a perspective view of a still further embodiment of a ladder-based plank scaffold system with ladder-mounted platform stabilizer or guide bars, and FIG. 1E is an enlarged view of one end of a support platform thereof.

FIG. 1F is a perspective view of yet another embodiment of a ladder-based plank scaffold system having an alternative arrangement of platform stabilizer bars;

FIG. 2A is a perspective view of an exemplary weight-bearing standoff used in the ladder-based plank scaffold system of the present application, and FIG. 2B is an alternative weight-bearing standoff.

FIG. 3A is a perspective view of an exemplary plank roller assembly used in the ladder-based plank scaffold system of the present application with a guide bar in the form of a round pipe engaged by concave rollers, and FIG. 3B is a variation using square tubing and flat rollers.

FIG. 4A is a perspective view of an alternative ladder-based plank scaffold system of the present application, FIG. 4B is a side elevational view thereof, FIG. 4C is a perspective view of a stabilizer/roller assembly incorporated therein, and FIG. 4D illustrates additional structural details.

FIG. 5 is a perspective view of another alternate embodiment of a ladder-based plank scaffold system.

FIG. 6A is a perspective view of a still further alternative ladder-based plank scaffold system with telescoping standoff arms, and FIG. 6B is a side elevational view thereof.

FIG. 7 is a perspective view of an alternative crane assembly which can be detached from the top of each ladder, and FIG. 7A is another crane assembly which can be detached from the top of each ladder.

FIG. 7B is a perspective view of an upper end of a modified ladder having an integrated standoff and crane extension;

FIG. 7C is a perspective view of an upper end of another modified ladder having an integrated standoff and crane extension that are hinged with respect to the ladder, and FIG. 7D is a partially exploded view of a similar modified ladder with a platform stabilizer bar connector removed;

FIG. 8 is a perspective view of a ladder-based plank scaffold system for use with step-ladders.

FIG. 9 is a perspective view of a tower scaffold variation of the present application.

FIG. 10 is a perspective view of a stage tower variation of the present application.

FIG. 11 is a perspective view of a tripod variation of the present application.

DETAILED DESCRIPTION

Unless defined otherwise, all terms of art, notations and other technical terms or terminology used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this disclosure belongs. All patents, applications, published applications and other publications referred to herein are incorporated by reference in their entirety. If a definition set forth in this section is contrary to or otherwise inconsistent with a definition set forth in the patents, applications, published applications, and other publications that are herein incorporated by reference, the definition set forth in this section prevails over the definition that is incorporated herein by reference.

Unless otherwise indicated or the context suggests otherwise, as used herein, “a” or “an” means “at least one” or “one or more.”

This description may use relative spatial and/or orientation terms in describing the position and/or orientation of a component, apparatus, location, feature, or a portion thereof. Unless specifically stated, or otherwise dictated by the context of the description, such terms, including, without limitation, top, bottom, above, below, under, on top of, upper, lower, left of, right of, in front of, behind, next to, adjacent, between, horizontal, vertical, diagonal, longitudinal, transverse, etc., are used for convenience in referring to such component, apparatus, location, feature, or a portion thereof in the drawings and are not intended to be limiting.

Furthermore, unless otherwise stated, any specific dimensions or specified thickness of materials mentioned in this description are merely representative of an exemplary implementation of a device embodying aspects of the invention and are not intended to be limiting.

FIG. 1A is a perspective view of an embodiment of a ladder-based plank scaffold system embodying aspects of the present application, and FIG. 1B is a side elevational view thereof. Key components of the system are indicated by letter symbols which correspond to descriptors provided below. The system is adapted to be deployed against a vertical wall W of varying heights, but typically no more than three stories tall, or about 21 feet. Practically speaking, standard 12′ extension ladders extend to 21′, which places the plank suspended below the top at about 16′. Of course, the present system can be scaled up to accommodate taller buildings, as permitted by regulation, though a typical system will have components that are small enough to be collapsed and transported in a standard work truck and deployed without special equipment. In a preferred embodiment, the system is portable, can be carried on a small truck, put up/taken down by one person in 30-45 minutes, and can bear at least 700 lbs.

The ladder-based plank scaffold system features two extension ladders D that are propped up against the wall W and spaced apart between 16-25 feet. A pair of loadbearing standoffs A that are secured at the top of each of the ladders D space the top end of the ladders away from the wall.

The wall standoffs A mount at the top of each of the ladders D and having a sufficient length to extend from the respective ladder to the adjacent vertical wall W. A crane support is fixedly connected to and positioned adjacent the top of each of the ladders, and a horizontal platform P is suspended on cables below the crane supports. The platform P has a pair of cable winches F mounted thereon for varying the elevation of the platform.

The wall standoff A and the crane support may be integrated into one structural piece. Each wall standoff A includes a vertical column with two ladder rung braces spaced to rest on top of different rungs of the ladder on which the wall standoff mounts. Each wall standoff includes a horizontal portion extending toward the adjacent vertical wall and terminating at a cable attachment mount such as a ring, wherein the cables for the cable winches are secured to the cable attachment ring. Upper and lower horizontal stabilizer bars extend from spaced points on each ladder D and connect firmly to a vertical roller guide bar GB positioned adjacent the vertical wall W, the horizontal platform P has a pair of roller assemblies I each of which engages and is configured to slide or roll up and down along one of the roller guide bars. The roller guide bar GB thus stabilize the platform P from rocking due to wind or other environmental factors.

Descriptors for FIGS. 1A and 1B:

A) Load-bearing standoff with crane. (Two versions, FIG. 2A, 2B)

GB) Roller guide bar (e.g., 2 inch aluminum pipe, 3/16 inch thick, or 2.5 inch aluminum square tube ⅛ inch thick).

C) Stabilizer bars (e.g., 1½ inch aluminum pipe, 3/16 inch thick).

D) Standard heavy-duty 12 foot extension ladders.

E) Cable fall breaks, standard commercial.

F) Electric winch, rechargeable.

G) Safety railings (e.g., 1½ inch aluminum pipe, 3/16 inch thick).

H) Plank frame (e.g., 1½ inch aluminum pipe, 3/16 inch thick).

I) Roller assembly, (see detail of FIGS. 3A and 3B).

FIG. 1C is a perspective view of an alternative embodiment of a ladder-based plank scaffold system similar to the first but without dedicated platform stabilizer or guide bars GB. As mentioned, the guide bars GB stabilize the platform P from rocking due to wind or other environmental factors. However, in certain situations such as indoors or when there is no wind, guide bars may not be needed. Otherwise, the system is constructed the same way and identical elements are given the same reference numbers. Namely, a platform P may be lifted up and down using an electric winch F via cables that are supported on a combined wall-standoff crane assembly A at the top of a pair of ladders D.

Alternatively, FIG. 1D shows a further ladder-based plank scaffold system with ladder-mounted platform stabilizer or guide bars GB. Instead of the guide bars GB extending vertically against the wall W in front of the platform P, as in FIG. 1A, the guide bars GB are instead attached to each of the ladders D at the rear of the platform. The guide bars GB are smaller in height than the earlier-described guide bars, and may attach via a horizontal struts to the ladders D. Those of skill in the art will understand a number of ways for connecting the struts firmly to the ladders.

FIG. 1E is an enlarged view of one end of a support platform P that may accommodate the guide bars GB at the rear side of the platform P. Instead of a pair of rollers that track the guide bars GB, a stirrup arrangement forms a plank frame and has a loop attached on a rear side of the platform. Each roller or guide bar GB extends through the loop and thus the platform P is stabilized from movement by the guide bar which is fixed to a ladder.

Finally, FIG. 1F is a perspective view of yet another embodiment of a ladder-based plank scaffold system having an arrangement of platform stabilizer or guide bars GB on both sides of the platform P. That is, taller guide bars GB extend along the wall W and may attach to the crane extension A, while shorter guide bars GB attach to the ladders D. This is essentially a combination of the first two embodiments. However, rather than providing rollers or loops attached to the platform P to track each of the guide bars GB, the platform is simply constrained between the four vertical bars.

An exemplary standoff A is illustrated in FIG. 2A and generally features brackets for connecting to the top of the ladders, a vertical column or crane extension B having a cantilevered horizontal component B′ extending toward the wall W, and a pair of standoff arms 2D that come in contact with the wall. The standoff arms 2D are connected to a mid-point of the crane extension B by horizontal components 2D′. The standoff arms 2D give the ladder wider upper contact points with the wall, and typically space the top of the ladder away from wall by 2 feet or more. Reinforcing plate gussets 2C are typically welded at angles of the components of the standoff A for strength. The standoff A is typically formed of aluminum as with most extension ladders for weight savings. Some commercial standoffs are referred to as bullhorn-type, as they have two arms like horns that are usually tipped with rubber feet or caps, such as shown at 2E.

Each standoff A has a lower portion that is angled with respect to the upper crane B. The lower portion has a pair of ladder rung braces in the form of inverted arcuate gussets 2G spaced to rest on top of different rungs of the ladder, and a pair of side lace plates 2H for each of the ladder rung braces 2G with apertures for passage of an elongated cotter pin 2F to lock the wall standoff to the ladder, as seen in FIG. 1A. The cotter pins pass through the respective rungs and the outer lace plates 2H to hold the standoff A in place. The lace plates 2H are shown spanning three rungs (1-3) and the rung braces 2G and cotter pins are associated with spaced apart rungs 1 and 3 for more strength, though they could be provided on rungs 1 and 2, or 1 and 4, or all three rungs 1, 2 and 3.

As indicated in the exemplary embodiment of FIG. 2A, the standoff arms 2D may have a length of 25 inches or more as allowed by regulations, and the upper rung brace or gusset 2G of the standoff A hangs on the top rung of the ladder D (FIG. 1A) so that there is enough space for the plank frame to rise as high as needed to get the plank to full height (e.g., 16′). The horizontal component B′ of the crane extension B terminates in a cable attachment mount such as a ring J through which a cable is passed, whose purpose will be clear below. It should be understood that a ring is an effective and efficient way to secure one end of a cable, though other types of mounts such as clamps or simple through holes in the crane extension B may be utilized. The term cable attachment mount covers all of these configurations.

FIG. 2B is an alternative weight-bearing standoff A which integrates the crane extension B with the standoff arms 2D. More particularly, the crane extension B has a vertical column, as before, with a horizontal component B′ attached to a top end and extending toward the wall W. The standoff arms 2D including a common horizontal component 2D′ attached to a free end of the horizontal component B′. Due to the horizontal component B′ of the crane extension B, the standoff arms 2D are significantly shorter than those in the embodiment of FIG. 2A.

Furthermore, the cable attachment ring J is positioned along the horizontal component B′ of the crane extension B which is no longer cantilevered, due to the bracing effect of the standoff arms 2D against the wall W. This helps distribute the weight of the platform, workers and materials more evenly as opposed to a cantilevered crane extension.

The standoff A further may include a lower portion that is angled and has a pair of ladder rung braces in the form of inverted arcuate gussets 2G spaced to rest on top of different rungs of the ladder. Lace pins 2FF may be used to pass through apertures in the gussets 2G and through the respective rungs to hold the standoff A in place.

The horizontal component B′ of the crane extension B may further terminate in a fastener bracket K, such as a square tube as shown, that is sized to be secured to a top end of a roller guide bar GB. The horizontal component B′ thus takes the place of an upper horizontal stabilizer bars C such as seen in the embodiment of FIG. 1A.

It should be noted that the cable winches F could be mounted remote from the platform P, such as on the horizontal component B′ of the crane extension B as in FIG. 2A, or on the horizontal component B′ as seen in FIG. 2B. Remotely controlled winches using wifi or Bluetooth are known.

Descriptors for FIGS. 2A and 2B:

A) Load-bearing standoff with crane.

B) Crane extension.

2C) Gussets, strength reinforcements.

2D) Standoff arms, (approximately 25″ long).

2E) Standoff feet, rubber/standard.

2F, 2FF) Through ladder rung, lace pins.

2G) Over rung standoff mounts, Ladderjack adapted/standard.

2H) Exterior ladder side lace plates.

2I) Cotter clips for lace pins.

J) Cable attachment ring.

K) Fastener bracket.

GB) Roller guide bar.

With reference back to FIGS. 1A and 1B, cables extend down from the two standoffs A to electric winches F mounted on a vertically-adjustable plank or platform P. An operator standing on the platform P can control the height of the plank by actuating the electric winches F. It should be noted that there are also cable drop brakes E mounted above the winches F, which will stop a freefall and are tripped if the cable goes too fast. Powerful cable winches are currently available for reasonable prices, and so two winches on either side of the platform P are typical, though systems that utilize just one winch are also encompassed by a winch system.

The system is stabilized from swaying excessively by a series of bars connected between the ladders D and platform P. In particular, horizontal stabilizer bars C extend from the upper and lower ends of the ladders D two vertical roller or guide bars GB positioned against the wall W. Small spacers such as horizontal pipe lengths may be provided between the guide bars GB and the wall. The guide bars GB are also received in roller assemblies I extending horizontally toward the wall W from the platform P. In this way, the components of the system are integrated stabilized against oscillations caused by the wind or other disturbances.

FIGS. 3A and 3B are perspective views of an exemplary plank roller assembly used in the ladder-based plank scaffold system of the present application. In the exemplary embodiment, the guide bar GB extends between a pair of concave rollers 3E (or flat rollers) so that the platform P is guided smoothly up and down adjacent wall W. Previously used swing stages have had a problem in that when working on one you must not touch or lean on the wall because you are hanging on ropes or cables, and if you do, it swings away from the wall. The illustrated stabilizer bars GB′, C ensure that the angle of the ladder is always the same (from Vertical Guide bar to ladder) and the distance between ladders also stay the same (from ladder to ladder.) It should be understood that the vertical roller or guide bars GB may be formed from several types of rigid lengths, most commonly round pipe or square tube, though solid and other cross-sections are possible. Also, some standard scaffold planks have premade mounting methods for roller wheels which may be used if practicable.

Descriptors for FIGS. 3A and 3B:

3A) Aluminum scaffold plank (e.g., 6″×14″×20′ max, holds 750 pounds).

GB) Roller guide bar (e.g., 2″ aluminum pipe, 3/16 inch thick or 2.5 inch square tube, ⅛ inch thick).

3C) Roller assembly attachment sleeve.

3D) Roller assembly (see detail FIG. 4C).

3E) Rollers.

3F) Rollers extension bar.

GB′) Roller guide bar stabilizer (e.g., 2″ aluminum pipe, 3/16 inch thick or 2.5 inch square aluminum tube, ⅛ inch thick).

FIGS. 4A and 4B illustrate an alternative ladder-based plank scaffold system of the present application, FIG. 4C is a perspective view of a stabilizer/roller assembly incorporated therein. The system is generally similar to that described above, but includes plank stabilizers for greater security. FIG. 4D illustrates additional structural details, in particular each roller assembly includes a pair of rollers that are movable with respect to one another to enable each pair of rollers to be assembled over one of the roller guide bars.

FIG. 5 is a perspective view of another alternate embodiment of a ladder-based plank scaffold system. In this variation, a horizontal stabilizer pole SP is mounted between the crane extensions that extend upward on the standoffs A for both ladders. The cables connect to the horizontal stabilizer pole SP. This allows for easier setup as opposed to suspending the cables from the standoffs. In addition, the weight bearing standoff A is connected directly to the vertical guide bar GB via a horizontal strut S. The vertical guide bar GB goes down to the ground so therefore the weight of the cables, brakes, winch, plank frame and planks are now distributed not only to the weight bearing standoffs A but also to that guide bar GB (and the ground), cutting the weight stress to the standoff A basically in half. Rather than using a separate horizontal stabilizer pole SP, the crane arm may extend all the way to the wall and bend downward so as to connect to the roller guide bar GB.

FIG. 6A is a perspective view of a still further alternative ladder-based plank scaffold system with telescoping standoff arms 6J, and FIG. 6B is a side elevational view thereof. This arrangement allows the standoffs A to be spaced variable distances away from the wall W. FIG. 6A also shows a version of the alternate standoff A of FIG. 2B in which the horizontal component connects to the roller guide bar GB.

Descriptors for FIGS. 6A and 6B:

A) Load-bearing standoff with crane (connected to roller guide bar GB).

GB) Roller guide bar (e.g., 2 inch aluminum pipe, 3/16 inch thick or 2.5 inch square aluminum tube, ⅛ inch thick).

C) Stabilizer bars (e.g., 1½ inch aluminum pipe, 3/16 inch thick).

D) Standard heavy-duty 12 foot extension ladders.

E) Cable fall breaks, standard commercial.

F) Electric winch, rechargeable.

G) Safety railings (e.g., 1½ inch aluminum pipe, 3/16 inch thick).

H) Plank frame (e.g., 1½ inch aluminum pipe, 3/16 inch thick).

I) Roller assembly, (see details of FIGS. 3A and 3B).

6J) Telescopic standoff arm.

FIG. 7 is a perspective view of an alternative crane assembly which can be detached from the top of each ladder. Separate standoffs with extended arms can then be provided for each of the ladders, rather than integrating the crane assembly with the ladder standoff. The alternative crane assembly does not have the ladder rung braces.

FIG. 7A is another crane assembly which can be detached from the top of each ladder. In this arrangement, a crane is fixed at an angle (e.g., 75°) at the top of a pair of linear mounting plates which may be secured to a ladder via lacing pins and corresponding cotter pins. That is, the lacing pins passed through apertures in each of the mounting plates and through a hollow rung of the ladder, being secured on both sides. There is no wall standoff in this configuration, though the crane may be configured to connect to a vertical guide or roller bar, as shown.

FIG. 7B is a perspective view of an upper end of a modified ladder having an integrated standoff and crane extension. More specifically, the ladder is not completely linear, but instead has approximately one terminal rung section is fixed at an angle to the rest of the ladder. To provide additional horizontal extension, a standoff arm passes through aligned through holes in the angled section and may terminate in rubber feet or other such high friction elements to help prevent sliding against the wall. The standoff arm may be rotatable within the through holes so that it can be collapsed, but is typically indexed so that it can be fixed at particular rotational angles. The modified ladder also may include a connector for attaching to a vertical guide or roller bar, such as shown in FIG. 7A.

FIG. 7C is a perspective view of an upper end of another modified ladder having an integrated standoff and crane extension that are hinged with respect to the ladder. In particular, a terminal rung section is hinged to rotate about a penultimate rung. The terminal rung section may be rotated to an angle as shown and then secured at an angle using a pair of diagonal support struts flanking the ladder with lacing pins which pass through hollow rungs and cotter keys to secure them in place. This hinged joint allows the terminal rung section to turn downwards at approximately 75 degree to the remaining portion of the ladder. By removing at least one of the lacing pins the terminal rung section may be rotated to lie flat against the rest of the latter or extends straight out linearly. A connector for attaching to a vertical guide or roller bar is also shown.

FIG. 7D is a partially view of a similar modified ladder with a platform guide or roller bar connector removed. The terminal rung section is shown rotated to be in parallel with the rest of the ladder, and a transport stabilizer which again assembles via hollow rungs may be included to maintain the linearity of the modified ladder during transport. One or more diagonal support struts as in FIG. 7C are not shown but may be included in the assembly.

Exemplary dimensions include 12 inches between rungs, and an additional 13 inches via a standoff bar.

FIG. 8 is a perspective view of a ladder-based plank scaffold system for use with step-ladders. Consequently, the system need not be propped up against a wall, which is beneficial in cases where the exterior surface of the wall is delicate or otherwise will not support the ladder/standoff weight.

FIG. 9 is a perspective view of a tower scaffold variation of the present application. This also is a standalone version that does not rely on support of an adjacent vertical wall. The crane assembly is provided by a horizontal upper bar 20 which leads to a vertical support bar 22. Instead of a ladder on each side, a tower scaffold 24 is used. A tower scaffold 24 may require more time and effort to erect, but provides somewhat greater stability to the entire structure and may be able to reach higher wall surfaces. Although this version is not strictly speaking “ladder-based,” it provides a similar portable temporary access structure for a vertically-adjustable plank, and is thus considered a suitable alternative.

FIG. 10 is a perspective view of a stage tower variation of the present application. The crane assembly is provided by a horizontal upper bar 30 which leads to a vertical support bar 32. Instead of a ladder on each side, a stage tower 34 is used. Although a stage tower 34 may require more time and effort to erect, it provides somewhat greater stability to the entire structure and may be able to reach higher wall surfaces. Again, although this version is not “ladder-based,” it provides a similar portable temporary access structure for a vertically-adjustable plank.

Finally, FIG. 11 is a perspective view of a tripod variation of the present application. As with the tower and stage tower variations described above, the use of two tripod-style ladders allows the scaffolding system to be established without need for leaning standoffs against the wall being worked on.

While the present invention has been described and shown in considerable detail with reference to certain illustrative embodiments, including various combinations and sub-combinations of features, those skilled in the art will readily appreciate other embodiments and variations and modifications thereof as encompassed within the scope of the present invention. Moreover, the descriptions of such embodiments, combinations, and sub-combinations is not intended to convey that the invention requires features or combinations of features other than those expressly recited in the claims. Accordingly, the present invention is deemed to include all modifications and variations encompassed within the spirit and scope of the following appended claims.

Closing Comments

Throughout this description, the embodiments and examples shown should be considered as exemplars, rather than limitations on the apparatus and procedures disclosed or claimed. Although many of the examples presented herein involve specific combinations of method acts or system elements, it should be understood that those acts and those elements may be combined in other ways to accomplish the same objectives. Acts, elements and features discussed only in connection with one embodiment are not intended to be excluded from a similar role in other embodiments.

As used herein, “plurality” means two or more. As used herein, a “set” of items may include one or more of such items. As used herein, whether in the written description or the claims, the terms “comprising”, “including”, “carrying”, “having”, “containing”, “involving”, and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of” and “consisting essentially of”, respectively, are closed or semi-closed transitional phrases with respect to claims. Use of ordinal terms such as “first”, “second”, “third”, etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements. As used herein, “and/or” means that the listed items are alternatives, but the alternatives also include any combination of the listed items. 

It is claimed:
 1. A ladder-based plank scaffold system, comprising: a pair of ladders; a wall standoff mounted at the top of each of the ladders, each wall standoff having at least one horizontally oriented arm having a length sufficient to extend from a respective ladder to an adjacent vertical wall, the wall standoff further having a crane support fixed thereto including a crane arm that extends horizontally toward the adjacent vertical wall and has a cable attachment mount thereon; a horizontal platform suspended below the crane supports on cables attached to the cable attachment mounts; and a cable winch system operatively engaging the cables for varying the elevation of the platform.
 2. The system of claim 1, wherein the wall standoff and the crane support are integrated into one structural piece that is removable from a respective ladder.
 3. The system of claim 2, wherein each wall standoff includes two ladder rung braces spaced to rest on top of different rungs of the ladder on which the wall standoff mounts.
 4. The system of claim 2, wherein each wall standoff includes a pair of side lace plates with apertures for passage of an elongated cotter pin sized to pass through ladder rungs and lock the wall standoff to the ladder.
 5. The system of claim 1, wherein each wall standoff includes a vertical column with ladder mounting structure, and two of the horizontally oriented arms that are connected to the vertical column and extend horizontally to the adjacent vertical wall.
 6. The system of claim 5, wherein each of the horizontally oriented arms has an adjustable length.
 7. The system of claim 1, further including a pair of vertical guide bars each positioned alongside the adjacent vertical wall in line with one of the ladders, wherein the at least one horizontally oriented arm of each wall standoff is secured to a vertical guide bar, the horizontal platform including guide structure which engages and is configured to be guided along the guide bars.
 8. The system of claim 1, further including a pair of vertical guide bars each positioned alongside the adjacent vertical wall in line with one of the ladders, and also including at least one horizontal stabilizer bar extending from each of the ladders toward the adjacent vertical wall and connected to a vertical guide bar, the horizontal platform including guide structure which engages and is configured to be guided along the guide bars.
 9. The system of claim 8, wherein the guide structure includes roller assemblies each of which engages and is configured to slide or roll up and down along one of the vertical guide bars.
 10. The system of claim 1, wherein the cable winch system includes a pair of electric cable winches and a cable fall break.
 11. A ladder-based plank scaffold system, comprising: a pair of ladders; a wall standoff mounted at the top of each of the ladders and having a length sufficient to extend from a respective ladder to an adjacent vertical wall, each wall standoff terminating at the adjacent vertical wall in two horizontally spaced apart arms for contacting the wall and stabilizing the ladder; a crane support fixedly connected to and positioned adjacent the top of each of the ladders, each crane support having a cable attachment mount thereon; a horizontal platform suspended below the crane supports on cables attached to the cable attachment mounts; and a cable winch system operatively engaging the cables for varying the elevation of the platform.
 12. The system of claim 11, wherein each wall standoff is integrated into a terminal rung section of a respective ladder.
 13. The system of claim 12, wherein the terminal rung section of each ladder may pivot with respect to a remainder of the ladder, and further including support struts for fixing an angle of the terminal rung section.
 14. The system of claim 11, wherein the wall standoff and the crane support are separate and each crane support includes a lower portion that is angled with respect to a vertical upper column, the lower portion having a pair of side lace plates for each of the ladder rung braces with apertures for passage of an elongated cotter pin to lock the crane support to the ladder.
 15. The system of claim 11, wherein the wall standoff and the crane support are integrated into one structural piece that is removable from a respective ladder, and each wall standoff includes two ladder rung braces spaced to rest on top of different rungs of the ladder on which the wall standoff mounts.
 16. The system of claim 11, wherein the wall standoff and the crane support are integrated into one structural piece that is removable from a respective ladder, and each wall standoff includes a pair of side lace plates with apertures for passage of an elongated cotter pin sized to pass through ladder rungs and lock the wall standoff to the ladder.
 17. The system of claim 11, wherein each of the horizontally oriented arms has an adjustable length.
 18. The system of claim 11, further including a pair of vertical guide bars each positioned alongside the adjacent vertical wall in line with one of the ladders, and also including at least one horizontal stabilizer bar extending from each of the ladders toward the adjacent vertical wall and connected to a vertical guide bar, the horizontal platform including guide structure which engages and is configured to be guided along the guide bars.
 19. The system of claim 18, wherein the guide structure includes roller assemblies each of which engages and is configured to slide or roll up and down along one of the vertical guide bars.
 20. The system of claim 11, wherein the cable winch system includes a pair of electric cable winches and a cable fall break. 